WLAN systems are ubiquitously used in today's communications systems, and, in particular, are used to connect mobile devices to the internet via an access point. The mobile devices can freely move in a local coverage, while still being connected to the WLAN via wireless distribution methods, e.g., by orthogonal frequency division multiplexing (“OFDM”) signals. WLAN systems have become popular due to its ease of installation and use.
Most modern WLAN systems are based on IEEE 802.11 standards, and marketed under the mark “Wi-Fi”. In particular, the 802.11a, 802.11n, 802.11ac, etc. standards are specific WLAN standards for band transmissions using OFDM signals. In some of these 802.11 standards, each channel is 20 MHz wide (or multiples of two thereafter), and the center frequencies of adjacent channels are 20 MHz apart (or multiples of two thereafter).
FIG. 1 illustrates channelization for the IEEE 802.11a, n, and ac standards. For the 802.11a standard, channels 10 can have a channel bandwidth of up to 20 MHz. For the 802.11n standard, channels 12 can have a channel bandwidth of up to 40 MHz. For the 802.11ac standard, channels 14 and 16 can have a channel bandwidth of up to 80 MHz or 160 MHz. Also, for the 802.11ac standard, adjacent 20 MHz subchannels can be grouped into pairs to make 40 MHz channels, and then adjacent 40 MHz subchannels can be grouped into pairs to make 80 MHz channels. Additionally, adjacent 80 MHz subchannels can be grouped into pairs to make the 160 MHz channels. Using a wider channel bandwidth can advantageously increase capacity, i.e., the transfer rate from a transmitter to a receiver. For instance, a 40 MHz channel has greater capacity than a 20 MHz channel, and so on.
As older and newer WLAN standards are concurrently used, devices (e.g., laptops, tablets, mobile phones, etc.) must be able to distinguish the various WLAN standards and channel bandwidth size. Accordingly, it is important to accurately determine the bandwidth between communicating devices. Current systems and devices typically rely on default bandwidth settings and/or query a user at application start-up to identify the bandwidth of their local system. However, most users do not know the bandwidth associated with their communications system. Thus, it would be beneficial to provide a mechanism to automatically detect the channel bandwidth of a communications system.